Ah, tat one. Yeah. Shep's a bit self conscious about her physical attributes. While she recognizes that she is in top form for combat, she doesn't think herself to be attractive )) If I'm making any sense )

Hmmm. You see this Shep not good at catching things like that. Just shows her abs to fellow marine. If there's any flirting going on there, she's not aware of it. Though Ash always says ma'am in that weird way. Maybe she is flirting with Shep )))